zublin



Feb. 14, 1956 J. A. zuBLlN, 2,734,721

` APPARATUS FOR DRILLING WELLS WITH ORIENTED CURVED BORES OF' LARGERADII Filed June 4, 1953 2 Sheets-Sheet l Feb. 14, 1956 Filed June 4,J1955 APPARATUS FOR CURVED J. ZUBLIN DRI NG WELLS WITH BORES OF' LARGERADI ORIENTED I 2 Sheets-Sheet 2 mxmmw INVENTOR United States PatentAPPARATUS FOR DRILLING WELLS WITH URI- ENTED CURVED BORES OR LARGE RADIIJohn A. Zublin, Los Angeles, Calif.

Application June 4, 1953, Serial No. 359,562

2 Claims. (Cl. 25E-1.6)

The present invention relates to apparatus for drilling oil wells withoriented curved bores of large radii. It is the purpose and object ofthe invention to provide a method and apparatus by which oriented curvedbores of large radii may be effectively drilled with but one round tripof the drilling equipment.

The need for the drilling of deecting bores having as their purpose therecovery of oil from points in a producing formation horizontally spaceda substantial distance from the point of initiation of the vertical wellbore has become increasingly pronounced with attempts to recover oilfrom underwater formations. Indeed there are many instances where thereal need for the drilling of a deflecting bore in a given azimuth isapparent.

It is the purpose and Iobject of the present invention to provide amethod and apparatus by which such a deflecting bore may be producedthrough conventional rotary drilling technique as a direct continuationof an initiated vertical well bore.

The present invention is not concerned with the production of curveddeviated bores of small radii such as drain holes drilled directly froma verticalbore laterally into the producing formation, but is ratherconcerned with the production of a deiiecting bore as a continuation ofan initially straight well bore in the drilling of which the bore isdeflected in a curved path of large radius on the order of 1000 to 2000feet.

In the prior art practice of the drilling of deflecting bores theexpedient of whipstocks has been primarily availed of. Generallyspeaking, tubular drill strings employed in rotary drilling havesuicient inherent ilexibility to permit of their deviation from thevertical in an amount approximating about 3 per hundred feet of lengthVof drill string. In general, whipstocks set in a vertical well bore forthe purpose of causing a deiiection of the drill bit 'normallycontemplate a deflection from the vertical of from around 3.to about 5.In practice it has been found that when drilling a deflecting borethrough the medium of a whipstock, the drill string after it passes thewhipstock tends to follow the path of least resistance and return to astraight line under the iniluence of gravity. In consequence of thisinherent tendency of the conventional rotary drill string to follow thepath of least resistance, it has been the prior art practice in thedrilling of deecting bores through the use of whipstocks to drill alimited distance beyond the point of setting a particular whipstock; tothen withdraw the drill string and bit from the well bore and setanother whipstock at a lower depth to which the deecting bore has beendrilled, and to repeat this procedure throughout the drilling of thedeilecting bore. Such practice has entailed the necessity for a completeroundtrip each time a whipstock is set. Each roundtrip and each settingof the whipstock entails hazards that, -quite apart from the sheer-lossof time involved, render the drilling of the dellecting bores of largeradii very costly. v-

ICC

It is the purpose and object of this invention to provide a simplifiedmethod and apparatus for drilling deilecting bores of large radii bywhich it is possible to eliminate the use of whipstocks and to completethe drilling of a deecting bore or a series of dellecting bores on oneroundtrip of the drilling equipment.

More specically, it is the object of the invention to provide a methodand apparatus for initiating and continuing the drilling of a deilectingbore at substantially the same fixed radius, said radius beingsufficiently large to lie within the limits of the inherent ilexibilityof the conventional rotary drill string.

From an apparatus standpoint, the purpose and object of the invention isto provide a unit suspendable from the lower end of a rotary drillstring susceptible of manipulations in a manner requisite to elect theinitiation and continued drilling of a curved deflecting bore of largeradius without the use of instrumentalities other than those suspendedfrom and carried by and insertable into the well bore by a conventionalrotary drill string.

By the expression curved bores of large radii as employed in thisapplication, it is intended to identify and define curved bores havingdegrees of curvature attainable through the inherent iiexibility of anormal rotary drill string. In general, the radii of deiiecting boreswith which the present invention is concerned lie within the limits ofabout 1000 to about 3000 feet.

Further purposes and objects of the invention will become apparent asthe description proceeds and will be described in connection with theaccompanying drawings, in which Figure 1 is a fragmentary view and sideelevation with parts broken away and illustrating a position of thedrilling unit suitable for practicing the method and exemplifying theapparatus of the invention;

.Figure 2 is a fragmentary view and side elevation with parts brokenaway similar in nature to Fig. l, and illustrating an additional speciesof the apparatus of the invention and a position of such apparatussuitable for practicing the method of the invention;

Figure 3 is a detailed cross sectional View illustrating the manner inwhich the deiiecting force is applied to the drilling in the unit;

Figure 4 is a detailed cross sectional view taken along the line 4 4 ofFig. 3;

Figure 5 is a detailed cross sectional view taken on the line 5-5`ofFig. 3;

Figure 6 is a detailed cross sectional view taken on the line 6--6 ofFig. 3;

Figure 7 is a detailed cross sectional view through the clutch mechanismillustrating operational features of the apparatus; and

Figure 8 is a detailed cross sectional view illustrating the manner inwhich the drilling unit may be suspended from a conventional rotarydrill string.

Referring to Figure 1, a conventional hollow rotary drill string isindicated at 10 which is adapted to extend to the surface of the welland to be rotated by conventional rotary equipment. Drilling uid isadapted to be passed down and through the drill string 10 from the lowerend of which is suspended a unit assembly embracing an inner tubularrotary drive member 11 which carries a bit 12 at its lower end. Rotationof the rotary drill string 10 and the rotary tubular drive member 11will effect a positive rotation of the bit 12. Surrounding the rotarydrive member 11 is an elongated sleeve i3, the upper end of which isthreadably engaged at 14 in a collar 15 carrying anti-friction means 16for facilitating free rotation of the tubular drive member 11 within thesleeve 13 (see Fig. 8). The sleeve 13 is slidable longitudinally to alimited extent on the member' :arsenal 11. Adjacent the upper end of thesleeve 13 there is positioned a stabilizing collar 17 having ribs 18.The stabilizing collar 17 is carried by the sleeve 13 and functions tostabilize the apparatus in the well bore.

The stabilizing collar 17 acts as a fulcrum about which the portions ofthe apparatus below the collar 17 can be moved.

Atl a point intermediate the stabilizing collar 17 and the bit 12 thereis provided an anchoring collar 19 ixedly held on the outer sleeve 13 bya set of screws 20 (see Fig. 4). Spaced below the collar 1.9 a slidablecollar 21 having a keyway 23 for the accompanying key 22, is mounted forrelative vertical movement on the exterior of the sleeve 13 (see Fig.5). A heavy leaf spring 24 adapted to exert a predetermined lateralforce on the drill unit has its upper end secured as indicated at 25 tothe collar 19 opposite the gripping teeth 26 thereof. The lower end ofthe leaf spring 24 is secured as indicated at 27 to the slidable collarZ1 opposite the gripping teeth 23 thereof. Stop members 29 are carriedby the sleeve 13 to limit the upper movement of the collar 21 on thesleeve 13.

Secured to the lower end of the sleeve 13 by the threaded connections 30is the upper member 31 of the two-clutch member. The lower member 32 ofthe twoclutch member is secured to and carried by the inner rotary drivemember 11. The spring 33 normally urges the clutch members 31 and 32toward the disengaged position. When, however, an upper pull is exertedon the rotary drill string 10, the frictional resistance offered u bythe stabilizing collar 17, the spring 24 and attendant mountings carriedby the outer sleeve 13, against the well bore wall will hold the sleeve13 thereby permitting limited vertical movement of the inner drivemember 11 and engagement of the clutch members 31 and 32 to permitconcurrent rotation of the inner drive member 11 and the sleeve 13 tofacilitate orientation of the sleeve 13. and to insure deflection of thebit 12 in the desired azimuth.

It will be appreciated that as the drilling of the deecting borecontinues the spring 24 tends to force the collars 19 and 21 toward theside of the bore with the smallest radius. When the teeth 26 and 28 ofthe collars 19 and 21 are pressed against the wall of the deilectingbore, the degree of deection will become stable and the bore willcontinue with substantially the same radius. The spring 24 continues tomaintain proper friction between the collar 19 and the wall of the wellbore whereby the member 13 is held against rotation as it advances inthe bore. clutch members 30 and 31 with the forced rotation of member 13will vary the azimuth of the deecting bore.

Only the closing of the It will also be appreciated that the weight ofthe sleeve f 13 and parts carried thereby is normally sufficiently inexcess of the frictional resistance or drag created by spring 24 and theribs on collars 17, 19 and 21 engaging with the well bore such that thesleeve normally moves along with the drill collar 11 and drill bit 12.

It may, in some instances, be advantageous to mount the collars 19 and21 on the member 13 other than concentrically therewith to furtherfacilitate orientation in the well.

By reference to Figure 1, it will be observed that the drilling unitshown has three points of contact with the well bore, point A being thecontact of the stabilizing collar 17 with the well bore; point B beingthe contact of the drill bit 12 with the well bore; and point C beingthe contact of the spring 24 with the well bore. The bit 12 rotates andits sharp teeth cut sidewardly into the well bore under the forcesupplied by spring 24 which tends to pivot the bit about the collar 17at point A as a fulcrum. Thus, after a few rotations of the drill stringwith the parts in the position shown in Figure. l, the bit initiates thedrilling sidewardly under the force of the spring 24. The bit is loweredsimultaneously with this sideward drilling tendency with the result thatthere is initiated the drilling of a curved bore of largev radiusdetermined by the three-point Contact of the unit within the well bore.

A generally equivalent structure is shown in Figure 2 which is identicalwith the structure shown in Figure l with the exception that therelative location of the stabilizing collar 17 and of the collar 19 andassociated parts, including the spring 24 and the slidable collar 21, isreversed. That is, the apparatus shown in Figure 2 partahes of thecharacteristics of a rst class lever whereas the apparatus of Figure 1partakes of the characteristics of a lever of the third class. Morespecilically, in the apparatus shown, in Figure 2 the spring 24 havingits contact point C with the well bore acts as a torce :o pivot theapparatus around the contact point A of the collar 17 which functions asa fulcrum and so to direct the bit 12 making Contact at B with the wellbore to drill a deflecting bore of the desired radius.

it will be understood that this invention contemplates, both withrespect to method and apparatus, all relative rotations at the points Aand B, and more specically of the collar 17 which functions as a fulcrumand the collar 19 and associated force applying spring 24 and slidablecollar 21.

It will be understood that the eiective pressure applied to the bit willdepend somewhat on the relative location of the points A, B and C, andthat by variation of the relationship of the points A, B and C and thedegree of pressure applied by the spring 24 at the point C, the degreeof deection of the bit can be quite accurately controlled within thelimits of elasticity of the rotary drill string 10.

While the invention is primarily intended to effect drilling of adeflecting bore as a continuation of an initiated vertical bore, it ispossible to take off from a vertical bore that has been previouslydrilled and drill a deecting bore in a predetermined azimuth from saidvertical bore.

Indeed, it is even possible to drill a second deecting bore after a rstbore in a given azimuth has been drilled. A slight pull on the drillstring 10 with limited partial rotation will elfect engagement of theclutch members 31 and' 32, following which the unit may be oriented in anew azimuth.

This application is a continuation-in-part of Zublin application Ser.No. 328,679- led December 30, 1952.

Having thus described my invention, what I claim is:

l. Apparatus for controlling the direction and extent of deviation of awell bore by the rotary drilling method comprising an elongatedrelatively iniiexible tubular section, an elongated drill collarrotatably mounted in said tubular section, a drill bit carried at thelower end of and rotatable with said drill collar, means at the upperend of said drill collar for connecting same to the lower end of arotary drill string for rotation therewith, a collar rigidly secured tosaid tubular section adjacent the lower end thereof and having outwardlyprojecting ribs engageable with the well bore wall to provide a fulcrumabout which said tubular section can pivot, and well bore. engagingdeecting means carried by said tubular section at a point spaced abovesaid collar acting to urge said inexible tubular section and said drillbit to pivot about said collar in a predetermined radial direction.

2. Apparatus for controlling the direction and extent of deviation of awell bore by the rotary drilling method comprising an elongatedrelatively inexible tubular Section, an elongated drill collar rotatablymounted in said tubular section and capable of limited longitudinalmovement relative to said tubular section, interengaging clutch elementscarried by said tubular section andv said drill collar respectively,means normally. holding said clutch elements. in disengaged positionwhile permitting engagementof said. clutch elementsupon limitedlongitudinal' movement of said drill collar within said tubular sec 5tion, a drill bit carried at the lower end of and rotatable with saiddrill collar, means at the upper end of said drill collar for connectngsame to the lower end of a rotary drill string for rotation therewithand which said tubular section can pivot and well bore engaging deectingmeans carried by said tubular section at a point spaced above saidcollar acting to urge said iniiexible tubular sectionand said drill bitto pivot about whereby said drill collar may be moved longitudinally 5Seid 0011er in e predetermined radial directionrelative to said tubularsection by lifting of the dn'll string for engagement of said clutchelements, a collar rigidly secured to said tubular section adjacent thelower end thereof and having outwardly projecting ribs engageable withthe well bore wall to provide a fulcrum about Anderson July 25, 1939Diehl et al. Sept. 14, 1943

